Research Papers

Simulation Technology on SOFC Durability With an Emphasis on Conductivity Degradation of ZrO2-Base Electrolyte

[+] Author and Article Information
Harumi Yokokawa

Institute of Industrial Science,
The University of Tokyo,
Tokyo 153-8505, Japan
e-mail: yokokawa@iis.u-tokyo.ac.jp

Haruo Kishimoto, Taro Shimonosono, Katsuhiko Yamaji

National Institute of Advanced Industrial
Science and Technology (AIST),
Ibaraki 305-8565, Japan

Mayu Muramatsu, Keiji Yashiro, Tatsuya Kawada

Graduate School of Environmental Studies,
Tohoku University,
Sendai 980-8579, Japan

Kenjiro Terada

International Research Institute
of Disaster Science,
Tohoku University,
Sendai 980-0845, Japan

1Present address: Department of Chemistry, Biotechnology, and Chemical Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan.

Manuscript received June 20, 2016; final manuscript received February 15, 2017; published online March 28, 2017. Assoc. Editor: Jan Van herle.

J. Electrochem. En. Conv. Stor. 14(1), 011004 (Mar 28, 2017) (19 pages) Paper No: JEECS-16-1083; doi: 10.1115/1.4036038 History: Received June 20, 2016; Revised February 15, 2017

Attempts have been made to simulate numerically the conductivity degradation of solid oxide fuel cell (SOFC) YSZ electrolyte; physicochemical model has been constructed on the basis of experimental conductivities of Pt/1%NiO-doped YSZ/Pt cells under OCV condition. The temperature effect was extracted from the time constant for degradation caused by one thermal activation process (namely Y-diffusion), whereas the oxygen potential effect was determined by those Raman peak ratios between the tetragonal and the cubic phases which linearly change in relation to the conductivity. The electrical properties of the YSZ electrolyte before and after the transformation are taken into account. The time constant is directly correlated with Y-diffusion with proper critical diffusion length (∼10 nm), while the Y-diffusion can be enhanced on the reduction of NiO; this gives rise to the oxygen potential dependence. The most important objective of simulating the conductivity degradation is to reproduce the oxygen potential profile shift on transformation. Detailed comparison between experimental and simulation results reveal that the shift of oxygen potential profile, therefore, the conductivity profile change inside the YSZ electrolyte can well account for the Raman spectra profile. This also reveals that with decreasing temperature, there appear other kinetic factors of weakening or diminishing enhancing effects by NiO reduction. This may be important in interpreting the ohmic losses in real stacks, because there are differences in time constant or in magnitude of degradation between the pellets and those industrial stacks in which transformation was confirmed by Raman spectroscopy.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.


Hosoi, K. , and Nakabaru, M. , 2009, “ Status of National Project for SOFC Development in Japan,” ECS Trans., 25(2), p. 11.
Hosoi, K. , Ito, M. , and Fukae, M. , 2011, “ Status of National Project for SOFC Development in Japan,” ECS Trans., 35(1), pp. 11–18.
Horiuchi, K. , 2013, “ Current Status of National SOFC Project in Japan,” ECS Trans., 57(1), pp. 3–10. [CrossRef]
Kadawaki, M. , 2015, “ Current Status of National SOFC Projects in Japan,” ECS Trans., 68(1), pp. 15–22. [CrossRef]
Yokokawa, H. , 2009, “ Overview of Solid Oxide Fuel Cell Degradation,” Handbook of Fuel Cells Fundamentals Technology and Application, Vol. 6, W. Vielstich , H. Yokokawa , and H. A. Gasteiger , eds., Wiley, Chichester, UK, pp. 923–932.
Yokokawa, H. , Sakai, N. , Horita, T. , and Yamaji, K. , 2009, “ Impact of Impurities on Materials Reliability in SOFC Stack/Modules,” Handbook of Fuel Cells Fundamentals Technology and Application, Vol. 6, W. Vielstich , H. Yokokawa , and H. A. Gasteiger , eds., Wiley, Chichester, UK, pp. 979–991.
Kishimoto, H. , Horita, T. , and Yokokawa, H. , 2013, “ Long Term Operating Stability,” Solid Oxide Fuel Cells: From Materials to System Modeling, T. S. Zhao and M. Ni , eds., RSC Publishing, London, pp. 288–326.
Yokokawa, H. , and Horita, T. , 2013, “ Solid Oxide Fuel Cell Materials: Durability, Reliability and Cost,” Encyclopedia of Sustainability Science and Technology, R. A. Meyers , ed., Springer-Verlag, New York, pp. 9934–9968.
Yokokawa, H. , Tu, H. , Iwanschitz, B. , and Mai, A. , 2008, “ Fundamental Mechanisms Limiting Solid Oxide Fuel Cell Durability,” J. Power Sources, 182(2), pp. 400–412. [CrossRef]
Yokokawa, H. , Horita, T. , Yamaji, K. , Kishimoto, H. , and Brito, M. E. , 2010, “ Materials Chemical Point of View for Durability Issues in Solid Oxide Fuel Cells,” J. Korean Ceram. Soc., 47(1), pp. 26–38. [CrossRef]
Yokokawa, H. , Yamaji, K. , Brito, M. E. , Kishimoto, H. , and Horita, T. , 2011, “ General Considerations on Degradation of SOFC Anodes and Cathodes Due to Impurities in Gases,” J. Power Sources, 196(17), pp. 7070–7075. [CrossRef]
Yokokawa, H. , Horita, T. , Yamaji, K. , Kishimoto, H. , and Brito, M. E. , 2012, “ Degradation of SOFC Cell/Stack Performance in Relation to Materials Deterioration,” J. Korean Ceram. Soc., 49(1), pp. 11–18. [CrossRef]
Yokokawa, H. , Horita, T. , Yamaji, K. , Kishimoto, H. , Yamamoto, T. , Yoshikawa, M. , Mugikura, Y. , and Tomida, K. , 2013, “ Chromium Poisoning of LaMnO3-Based Cathode Within Generalized Approach,” Fuel Cells, 13(4), pp. 526–535. [CrossRef]
Yokokawa, H. , 2015, “ Towards Comprehensive Description of Stack Durability/Reliability Behavior,” Fuel Cells, 15(4), pp. 652–668. [CrossRef]
Yokokawa, H. , 2015, “ Current Status of Rapid Evaluation of Durability of Six SOFC Stacks Within NEDO Project,” ECS Trans., 68(1), pp. 1827–1836. [CrossRef]
Suzuki, M. , Takuwa, Y. , Inoue, S. , and Higaki, K. , 2013, “ Durability Verification of Residential SOFC CHP System,” ECS Trans., 57(1), pp. 309–314. [CrossRef]
Miyamoto, K. , Mihara, M. , Oozawa, H. , Hiwatashi, K. , Tomida, K. , Nishiura, M. , Kishizawa, H. , Mori, R. , and Kobayashi, Y. , 2015, “ Recent Progress of SOFC Combined Cycle System With Segmented-in-Series Tubular Type Cell Stack at MHPS,” ECS Trans., 68(1), pp. 51–58. [CrossRef]
Mori, N. , Sato, Y. , Nakai, H. , Iha, M. , Takada, T. , and Konoike, T. , 2015, “ Development of a Novel Co-Fired SOFC at Murata,” ECS Trans., 68(1), pp. 1871–1878. [CrossRef]
Yoshikawa, M. , Yamamoto, T. , Asano, K. , Yasumoto, K. , and Mugikura, Y. , 2015, “ Performance Degradation Analysis of Different Type SOFCs,” ECS Trans., 68(1), pp. 2199–2208. [CrossRef]
Mugikura, Y. , Yasumoto, K. , Morita, H. , Yoshikawa, M. , and Yamamoto, T. , 2013, “ Performance Evaluation Technology for Long Term Durability and Reliability of SOFCs,” ECS Trans., 57(1), pp. 649–656. [CrossRef]
Inoue, S. , Nonaka, H. , Saito, T. , Yoda, M. , Nakao, T. , and Takuwa, Y. , 2015, “ High Durability Electrodeposition Painting for SOFC Metal Interconnector,” ECS Trans., 68(1), pp. 1589–1596. [CrossRef]
Mori, N. , Sato, Y. , Iha, M. , Takada, T. , Konoike, T. , Kishimoto, H. , Yamaji, K. , and Yokokawa, H. , 2015, “ Sulfur Poisoning of LSCF Cathode in Single Step Co-Fired SOFC,” ECS Trans., 68(1), pp. 1015–1022. [CrossRef]
Matsui, T. , Kim, J.-Y. , Muroyama, H. , Shimazu, M. , Abe, T. , Miyao, M. , and Eguchi, K. , 2012, “ Anode Microstructure Change Upon Long-Term Operation for the Cathode-Supported Tubular-Type SOFC,” Solid State Ionics, 225, pp. 50–54. [CrossRef]
Kanae, S. , Toyofuku, Y. , Kawabata, T. , Inoue, Y. , Daigo, T. , Matsuda, J. , Chou, J.-T. , Shiratori, Y. , Taniguchi, S. , and Sasaki, K. , 2015, “ Microstructural Characterization of SrZrO3 Formation and the Influence to SOFC Performance,” ECS Trans., 68(1), pp. 2463–2470. [CrossRef]
Terada, K. , Kawada, T. , Sato, K. , Iguchi, F. , Yashiro, K. , Amezawa, K. , Kubo, M. , Yugami, H. , Hashida, T. , Mizusaki, J. , Watanabe, H. , Sasagawa, T. , and Aoyagi, H. , 2011, “ Multiscale Simulation of Electro-Chemo-Mechanical Coupling Behavior of PEN Structure Under SOFC Operation,” ECS Trans., 35(1), pp. 923–933.
Muramatsu, M. , Kishimoto, H. , Yamaji, K. , Yashiro, K. , Kawada, T. , Terada, K. , and Yokokawa, H. , 2015, “ Electro-Chemical Potential Analysis of Zirconium Based on the Reaction-Diffusion Equations of Oxygen Ion and Electron Considering Phase Transformation,” ECS Trans., 68(1), pp. 2363–2372. [CrossRef]
Miyoshi, K. , Miyamae, T. , Iwai, H. , Saito, M. , Kishimoto, M. , and Yoshida, H. , 2015, “ Evaluation of Exchange Current Density for LSM Porous Cathode Based on Measurement of Three-Phase Boundary Length,” ECS Trans., 68(1), pp. 657–664. [CrossRef]
Jiao, Z. , Shimura, T. , and Shikazono, N. , 2015, “ Numerical Assessment of SOFC Anode Polarization With Microstructure Evolution,” ECS Trans., 68(1), pp. 1281–1289. [CrossRef]
Taniguchi, S. , Kadowaki, M. , Kawamura, H. , Yasuo, T. , Akiyama, Y. , Miyake, Y. , and Saitoh, T. , 1995, “ Degradation Phenomena in the Cathode of a Solid Oxide Fuel Cell With an Alloy Separator,” J. Power Sources, 55(1), pp. 73–79. [CrossRef]
Yokokawa, H. , Horita, T. , Sakai, N. , Yamaji, J. , Brito, M. E. , Xiong, Y. P. , and Kishimoto, H. , 2006, “ Thermodynamic Considerations on Cr Poisoning in SOFC Cathodes,” Solid State Ionics, 177(35–36), pp. 3193–3198. [CrossRef]
Xiong, Y. P. , Yamaji, K. , Horita, T. , Yokokawa, H. , Akikusa, J. , Eto, H. , and Inagaki, T. , 2009, “ Sulfur Poisoning of SOFC Cathodes,” J. Electrochem. Soc., 156(5), pp. B588–B592. [CrossRef]
Wang, F. , Yamaji, K. , Cho, D.-H. , Shimonosono, T. , Kishimoto, H. , Brito, M. E. , Horita, T. , and Yokokawa, H. , 2011, “ Sulfur Poisoning on La0.6Sr0.4Co0.2Fe0.8O3 Cathode for SOFCs,” J. Electrochem. Soc., 158(11), pp. B1391–B1397. [CrossRef]
Kishimoto, H. , Wang, F. , Cho, D. H. , Lv, P. , Bagarinao, K. D. , Yamaji, K. , Horita, T. , and Yokokawa, H. , 2015, “ Degradation of LSCF Cathode Induced by SO2 in Air,” ECS Trans., 68(1), pp. 1045–1050. [CrossRef]
Wang, F. , Kishimoto, H. , Develos-Bagarinao, K. , Yamaji, K. , Horita, T. , and Yokokawa, H. , 2016, “ Interrelation Between Sulfur Poisoning and Performance Degradation of LSCF Cathode for SOFCs,” J. Electrochem. Soc., 163(8), pp. F899–F904. [CrossRef]
Uchida, H. , Yoshida, M. , and Watanabe, M. , 1995, “ Effects of Ionic Conductivities of Zirconia Electrolytes on Polarization Properties of Platinum Anodes in Solid Oxide Fuel Cells,” J. Phys. Chem., 99(10), pp. 3282–3287. [CrossRef]
Uchida, H. , Yoshida, M. , and Watanabe, M. , 1999, “ Effect of Ionic Conductivity of Zirconia Electrolytes on the Polarization Behavior of Various Cathodes in Solid Fuel Cells,” J. Electrochem. Soc., 146(1), pp. 1–7. [CrossRef]
Kondoh, J. , Kawashima, T. , Kikuchi, S. , Tomii, Y. , and Ito, Y. , 1998, “ Effect of Aging on Yttria-Stabilized Zirconia: I. A Study of Its Electrochemical Properties,” J. Electrochem. Soc., 145(5), pp. 1527–1536. [CrossRef]
Kondoh, J. , Kikuchi, S. , Tomii, Y. , and Ito, Y. , 1998, “ Effect of Aging on Yttria-Stabilized Zirconia: II. A Study of Effects of the Microstructure on Conductivity,” J. Electrochem. Soc., 145(5), pp. 1536–1550. [CrossRef]
Kondoh, J. , Kikuchi, S. , Tomii, Y. , and Ito, Y. , 1998, “ Effect of Aging on Yttria-Stabilized Zirconia: III. A Study of the Effect of Local Structure on Conductivity,” J. Electrochem. Soc., 145(5), pp. 1550–1560. [CrossRef]
Kondoh, J. , Shiota, H. , Kikuchi, S. , Tomii, Y. , Ito, Y. , and Kawachi, K. , 2002, “ Changes in Aging Behavior and Defect Structure of Y2O3 Fully Stabilized ZrO2 by In2O3 Doping,” J. Electrochem. Soc., 149(8), pp. J59–J72. [CrossRef]
Nomura, K. , Mizutani, Y. , Kawai, M. , Nakamura, Y. , and Yamamoto, O. , 2000, “ Aging and Raman Scattering Study of Scandia and Yttria Doped Zirconia,” Solid State Ionics, 132(3–4), pp. 235–239. [CrossRef]
Hattori, M. , Takeda, Y. , Lee, J. H. , Ohara, S. , Mukai, K. , and Fukui, T. , 2004, “ Effect of Aging on Conductivity of Yttria Stabilized Zirconia,” J. Power Sources, 126(1–2), pp. 23–27. [CrossRef]
Takahashi, S. , Sakaki, Y. , and Nakanishi, A. , 2004, “ Effect of Annealing on the Electrical Conductivity of the Y2O3-ZrO2 System,” J. Power Sources, 131(1–2), pp. 247–250. [CrossRef]
Butz, B. , Kruse, P. , Störmer, H. , Gerthsen, D. , Müller, A. , Weber, A. , and Ivers-Tiffée, E. , 2006, “ Correlation Between Microstructure and Degradation in Conductivity for Cubic Y2O3-Doped ZrO2,” Solid State Ionics, 177(37–38), pp. 3275–3284. [CrossRef]
Terner, M. R. , Schuler, J. A. , Mai, A. , and Penner, D. , 2014, “ On the Conductivity Degradation and Phase Stability of Solid Oxide Fuel Cell (SOFC) Zirconia Electrolytes Analysed Via XRD,” Solid State Ionics, 263, pp. 180–189. [CrossRef]
Van Herle, J. , and Vasquez, R. , 2004, “ Conductivity of Mn and Ni-Doped Stabilized Zirconia Electrolyte,” J. Eur. Ceram. Soc., 24(6), pp. 1177–1180. [CrossRef]
Kwon, O. H. , and Choi, G. M. , 2006, “ Electrical Conductivity of Thick Film YSZ,” Solid State Ionics, 177(35–36), pp. 3057–3062. [CrossRef]
Linderoth, S. , Bonanos, N. , Jensen, K. V. , and Bilde-Sørensen, J. B. , 2001, “ Effect of NiO-to-Ni Transformation of Conductivity and Structure of Yttria-Stabilized ZrO2,” J. Am. Ceram. Soc., 84(11), pp. 2652–2656. [CrossRef]
Kondo, H. , Sekino, T. , Kusunose, T. , Nakayama, T. , Yamamoto, Y. , and Niihara, K. , 2003, “ Phase Stability and Electrical Property of NiO-Doped Yttria-Stabilized Zirconia,” Mater. Lett., 57(9–10), pp. 1624–1628. [CrossRef]
Coors, W. G. , O'Brien, J. R. , and White, J. T. , 2009, “ Conductivity Degradation of NiO-Containing 8YSZ and 10YSZ Electrolyte During Reduction,” Solid State Ionics, 180(2–3), pp. 246–251. [CrossRef]
Butz, B. , Lefarth, A. , Störmer, H. , Utz, A. , Ivers-Tiffée, E. , and Gerthsen, D. , 2012, “ Accelerated Degradation of 8.5 mol% Y2O3-Doped Zirconia by Dissolved Ni,” Solid State Ionics, 214, pp. 37–44. [CrossRef]
Kishimoto, H. , Shimonosono, T. , Yamaji, K. , Brito, M. E. , Horita, T. , and Yokokawa, H. , 2011, “ Phase Transformation of Stabilized Zirconia on SOFC Stacks,” ECS Trans., 35(1), pp. 1171–1176.
Shimonosono, T. , Kishimoto, H. , Yamaji, K. , Brito, M. E. , Horita, T. , and Yokokawa, H. , 2012, “ Phase Transformation Related Electrical Conductivity Degradation of NiO Doped YSZ,” Solid State Ionics, 225, pp. 69–72. [CrossRef]
Kishimoto, H. , Yashiro, K. , Shimonosono, T. , Brito, M. E. , Yamaji, K. , Horita, T. , Yokokawa, H. , and Mi-Zusaki, J. , 2012, “ In Situ Analysis on the Electrical Conductivity Degradation of NiO Doped Yttria Stabilized Zirconia Electrolyte by Micro-Raman Spectroscopy,” Electrochem. Acta, 82, pp. 263–267. [CrossRef]
Shimonosono, T. , Kishimoto, H. , Nishi, M. , Brito, M. E. , Yamaji, K. , Yokokawa, H. , and Horita, T. , 2013, “ Cubic—Tetragonal Phase Transformation of YSZ Electrolyte in SOFCs,” ECS Trans., 57(1), pp. 627–634. [CrossRef]
Yokokawa, H. , Sakai, N. , Horita, T. , Yamaji, K. , and Brito, M. E. , 2005, “ Solid Oxide Electrolytes for High Temperature Fuel Cells,” Electrochemistry, 73(1), pp. 20–30.
Yokokawa, H. , Sakai, N. , Horita, T. , Yamaji, K. , and Brito, M. E. , 2005, “ Electrolytes for Solid Oxide Fuel Cells,” Mater. Bull., 30(8), pp. 591–595. [CrossRef]
Shimonosono, T. , Kishimoto, H. , Yamaji, K. , Brito, M. E. , Horita, T. , and Yokokawa, H. , 2012, “ Electronic Conductivity of Ni-Doped Yttria-Stabilized Zirconia,” Solid State Ionics, 225, pp. 61–64. [CrossRef]
Shimazu, M. , Isobe, T. , Ando, S. , Hiwatashi, K. , Ueno, A. , Yamaji, K. , Kishimoto, H. , Yokokawa, H. , Nakajima, A. , and Okada, K. , 2011, “ Stability of Sc2O3 and CeO2 Co-Doped ZrO2 Electrolyte During the Operation of Solid Oxide Fuel Cells,” Solid State Ionics, 182(1), pp. 120–126. [CrossRef]
Shimazu, M. , Yamaji, K. , Isobe, T. , Ueno, A. , Kishimoto, H. , Katsumata, K. , Yokokawa, H. , and Okada, K. , 2011, “ Stability of Sc2O3 and CeO2 Co-Doped ZrO2 Electrolyte During the Operation of Solid Oxide Fuel Cells—Part II: The Influences of Mn, Al and Si,” Solid State Ionics, 204–205, pp. 120–128.
Shimazu, M. , Yamaji, K. , Kishimoto, H. , Ueno, A. , Isobe, T. , Ka-tsumata, K.-I. , Yokokawa, H. , and Okada, K. , 2012, “ Stability of Sc2O3 and CeO2 Co-Doped ZrO2 Electrolyte During the Operation of Solid Oxide Fuel Cells—Part III: Detailed Mechanism of the Decomposition,” Solid State Ionics, 224, pp. 6–14. [CrossRef]
Yamaji, K. , Kishimoto, H. , Brito, M. E. , Horita, T. , Yokokawa, H. , Shimazu, M. , Yashiro, K. , Kawada, T. , and Mizusaki, J. , 2013, “ Effect of Mn-Doping on Stability of Scandia Stabilized Zirconia Electrolyte Under Dual Atmosphere of Solid Oxide Fuel Cells,” Solid State Ionics, 247–248, pp. 102–107. [CrossRef]
Malzbender, J. , Batfalsky, P. B. , Vassen, R. , Shemet, V. , and Tietz, F. , 2012, “ Component Interactions After Long-Term Operation of an SOFC Stack With LSM Cathode,” J. Power Sources, 201, pp. 196–203. [CrossRef]
Menzler, N. H. , Batfalsky, P. , Beez, A. , Blum, L. , Gross-Barsnick, S.-M. , Niewolak, L. , Quadak-Kers, W. J. , and Vassen, R. , 2016, “ Post-Test Analysis of a Solid Oxide Fuel Cell Stack Operated for 35,000 h,” 12th European SOFC and SOE Forum, Lucerne, Switzerland, July 5–8, p. A1101.
Yokokawa, H. , 2003, “ Understanding Materials Compatibility,” Annu. Rev. Mater. Res., 33(1), pp. 581–610. [CrossRef]
Choudhury, N. S. , and Patterson, J. W. , 1971, “ Performance Characteristics of Solid Electrolytes Under Steady State Conditions,” J. Electrochem. Soc., 118(9), pp. 1398–1403. [CrossRef]
Kawada, T. , and Yokokawa, H. , 1997, “ Materials and Characterization of Solid Oxide Fuel Cell,” Key Eng. Mater., 125–126, pp. 187–248. [CrossRef]
Wagner, C. , 1957, “Galvanic Cells With Solid Electrolytes Involving Ionic and Electronic Conduction,” International Committee of Electrochemical Thermodynamics and Kinetics, Proceedings of the Seventh Meeting, Vol. 1955, Butterworths, London, pp. 361–377.
Lee, D.-K. , and Yoo, H.-I. , 2006, “ Electron-Ion Interference and Onsager Reciprocity in Metal Ionic-Electronic Transport in TiO2,” Phys. Rev. Lett., 97, p. 255901. [CrossRef] [PubMed]
Chatzichristodoulou, C. , Park, W.-S. , Kim, H.-S. , Hendriksen, P. V. , and Yoo, H.-I. , 2010, “ Experimental Determination of the Onsager Coefficients of Transport for Ce0.8Pr.2O2-δ,” Phys. Chem. Chem. Phys., 12(33), pp. 9637–9649. [CrossRef] [PubMed]
Park, J. H. , and Blumenthal, R. N. , 1989, “ Electronic Transport in 8 Mole Percent Y2O3-ZrO2,” J. Electrochem. Soc., 136(10), pp. 2867–2876. [CrossRef]
Weppner, W. , 1977, “ Electronic Transport Properties and Electrically Induced p-n Junction in ZrO2 + 10 m/o Y2O3,” J. Solid State Chem., 20(3), pp. 305–314. [CrossRef]
Yashima, M. , Kahihana, M. , and Yoshimura, M. , 1996, “ Metastable-Stable Phase Diagrams in the Zirconia-Containing Systems Utilized in Solid-Oxide Fuel Cell Application,” Solid State Ionics, 86–88(Pt. 2), p. 1131. [CrossRef]
Hillert, M. , and Sakuma, T. , 1991, “ Thermodynamic Modeling of the c → t Transformation in ZrO2 Alloys,” Acta Metall. Mater., 39(6), pp. 1111–1115. [CrossRef]
Shibata, N. , Katamura, J. , Kuwabara, A. , Ikuhara, Y. , and Sakuma, T. , 2001, “ The Instability and Resulting Phase Transition of Cubic Zirconia,” Mater. Sci. Eng. A, 312(1–2), pp. 90–98. [CrossRef]
Lughi, V. , and Clarke, D. R. , 2005, “ High Temperature Aging of YSZ Coatings and Subsequent Transformation at Low Temperature,” Surf. Coat. Technol., 200(5–6), pp. 1287–1291. [CrossRef]
Krogstad, J. A. , Krämer, S. , Lipkin, D. M. , Johnson, C. A. , Mitchell, D. R. G. , Cairney, J. M. , and Levi, C. G. , 2011, “ Phase Stability of t′-Zirconia-Based Thermal Barrier Coatings: Mechanistic Insights,” J. Am. Ceram. Soc., 94(S1), pp. S168–S177. [CrossRef]
Limarga, A. M. , Iveland, J. , Gentleman, M. , Lipkin, D. M. , and Clarke, D. R. , 2011, “ The Use of Larson-Miller Parameters to Monitor the Evolution of Raman Lines of Tetragonal Zirconia With High Temperature Aging,” Acta Mater., 59(3), pp. 1162–1167. [CrossRef]
Lipkin, D. M. , Krogstad, J. A. , Gao, Y. , Johnson, C. A. , Nelson, W. A. , and Levi, C. G. , 2013, “ Phase Evolution Upon Aging of Air-Plasma Sprayed t′-Zirconia Coatings: I—Synchrotron X-Ray Diffraction,” J. Am. Ceram. Soc., 96(1), pp. 290–298. [CrossRef]
Krogstad, J. A. , Leckie, R. M. , Krämer, S. , Cairney, J. M. , Lipkin, D. M. , Johnson, C. A. , and Levi, C. G. , 2013, “ Phase Evolution Upon Aging of Air Plasma Sprayed t′-Zirconia Coatings: II—Microstructure Evolution,” J. Am. Ceram. Soc., 96(1), pp. 299–307. [CrossRef]
Hillert, M. , 1991, “ Thermodynamic Model of the Cubic → Tetragonal Transition in Nonstoichiometric Zirconia,” J. Am. Ceram. Soc., 74(8), pp. 2005–2006. [CrossRef]
Katsumura, J. , and Sakuma, T. , 1997, “ Thermodynamic Analysis of the Cubic-Tetragonal Phase Equilibria in the System ZrO2-YO1.5,” J. Am. Ceram. Soc., 80(10), pp. 2685–2688. [CrossRef]
Kawada, T. , Sakai, N. , Yokokawa, H. , and Dokiya, M. , 1992, “ Electrical Properties of Transition Metal Doped YSZ,” Solid State Ionics, 53–56(Pt. 1), pp. 418–425. [CrossRef]
Shimonosono, T. , 2013, “ Ionic Conductivity of NiO-Doped YSZ Before and After the Transformation at 900 °C With H2/1% H2O Atmosphere,” unpublished.
Kilo, M. , Borchardt, G. , Lesage, B. , Weber, S. , Scherrer, S. , Martin, M. , and Schroeder, M. , 2001, “ Zr and Stabilizer Tracer Diffusion in Calcia- and Yttria-Stabilized Zirconia,” Solid Oxide Fuel Cells VII (SOFC VII): Proceedings of the International Symposium, Vol. 2001–16, Electrochemical Society, Pennington, NJ, pp. 275–283.
Kilo, M. , Taylor, M. A. , Argirusis, C. , Borchardt, G. , Lesage, B. , Weber, S. , Scherrer, S. , Scherrer, H. , Schroeder, M. , and Martin, M. , 2003, “ Cation Self-Diffusion of 44Ca, 88Y, and 96Zr in Single-Crystalline Calcia- and Yttria-Doped Zirconia,” J. Appl. Phys., 94(12), p. 7547. [CrossRef]
Kilo, M. , Borchardt, G. , Lesage, B. , KaıüTasov, O. , Weber, S. , and Scherrer, S. , 2000, “ Cation Transport in Yttria Stabilized Cubic Zirconia: 96Zr Tracer Diffusion in (ZrxY1–x)O2–x/2 Single Crystals With 0.15⩽×⩽0.48,” J. Eur. Ceram. Soc., 20(12), pp. 2069–2077. [CrossRef]
Argirusis, C. , Taylor, M. A. , Kilo, M. , Borchardt, G. , Jomard, F. , Lesage, B. , and Kaïtasov, O. , 2004, “ SIMS Study of Transition Metal Transport in Single Crystalline Yttria Stabilized Zirconia,” Phys. Chem. Chem. Phys., 6(13), pp. 3650–3653. [CrossRef]
Kishimoto, H. , Brito, M. E. , Sakai, N. , Yamaji, K. , Horita, T. , Xiong, Y.-P. , and Yokokawa, H. , 2008, “ Difference in Cation Diffusion Between ScSZ and YSZ Electrolytes/LSM Cathode Interfaces,” 75th Meeting of Japanese Electrochemical Society, Yamanashi, Japan, Mar. 29–31, Paper No. 2B01.
Morrissey, A. , O'Brien, J. R. , and Reimanis, I. E. , 2016, “ Microstructure Evolution During Internal Reduction of Polycrystalline Nickel-Doped Yttria-Stabilized Zirconia,” Acta Mater., 105, pp. 84–93. [CrossRef]
Janek, J. , and Korte, C. , 1999, “ Electrochemical Blackening of Yttria-Stabilized Zirconia—Morphological Instability of the Moving Reduction Front,” Solid State Ionics, 116(3–4), pp. 181–195. [CrossRef]
Wright, D. A. , Thorp, J. S. , Aypar, A. , and Buckley, H. P. , 1973, “ Optical Absorption in Current-Blackened Yttria Stabilized Zirconia,” J. Mater. Sci., 8(6), pp. 876–882. [CrossRef]
Savoini, B. , Ballesteros, C. , Santiuste, J. E. M. , and Gonzalez, R. , 1998, “ Thermochemical Reduction of Yttria-Stabilized-Zirconia Crystals: Optical and Electron Microscopy,” Phys. Rev. B, 57(21), pp. 13439–13447. [CrossRef]


Grahic Jump Location
Fig. 1

Current status of performance analyses made by CRIEPI (as of July 2015)

Grahic Jump Location
Fig. 9

The electron conductivity of 1 mol % NiO added YSZ [58] compared with no NiO-doped YSZ [83]. The electron conductivity is lowered, whereas the hole conductivity is unchanged, leading to shift of the borderline between the oxidative and reductive regions to the fuel side.

Grahic Jump Location
Fig. 2

(a) Schematic distributions of oxygen potential, electrochemical potentials of oxide ions, and electrons inside YSZ electrolyte: comparison with the individual contributions from cathode/anode overpotential, cathode/anode Nernst term, ohmic loss in electrolyte, cathode and anode to be determined as average values in stack performance test in the NEDO durability projects. Although only the total ohmic loss is detected, other contributions will determine oxygen potential values at two ends of electrolyte. Available electrical data inside electrolyte enable division into the oxidative and the reductive regionin terms of the NiO reduction. (b) The electron conductivity minimum line which provides a borderline between the electron- and hole-dominant conductive regions. It compares with oxygen potentials in air and in fuel (H2/H2O) and also with that for the NiO/Ni redox equilibrium. (c) Factors of shifting the border position between the reductive and oxidative regions inside YSZ electrolytes. Those factors are originated from electrical characteristics of electrolyte and their degradation, change in operation temperature, electrode performance characterized as overpotential, and its change with operation time.

Grahic Jump Location
Fig. 13

Normalized Raman peak area ratio of tetragonal-related peaks to cubic-related peak as a function of temperature. Normalization is made using the peak ratio for 3YSZ in which the tetragonal peak becomes significantly large; solid circle is for 1 mol % NiO-doped 8YSZ (8 mol % stabilized ZrO2) and solid square being for 1 mol % NiO-doped 10YSZ (10 mol % Y2O3 stabilized ZrO2).

Grahic Jump Location
Fig. 10

Comparison in position of redox borderlines between inflection point of Raman data and those two NiO reduction fronts calculated from different sets of electrical conductivities for the initial and the final stages of transformation

Grahic Jump Location
Fig. 11

Two logarithmic time constants for conductivity degradation in 1 mol % NiO-doped YSZ as a function of inverse temperature; solid circles are for the anode side, small open squares being for the cathode side. Large square and triangle solid symbols are for 1 mol % NiO-doped 8YSZ in fuel [50,51], and large square and triangle open circles being for nondoped YSZ in air [37,4144]. Solid line is modeled time constant for NiO-doped 8YSZ in anode, the dashed line is obtained for YSZ in air under the assumption that the activation energy should be the same as that in the anode side. This means that at any temperature, about two orders of magnitude difference exists between two cases.

Grahic Jump Location
Fig. 12

Simulation results at 1173 K for LSCF/1%NiO YSZ/Ni-YSZ cells: (a) time-dependent oxygen potential distribution in the cells. After the development of oxygen potential distribution under dual atmospheres, oxygen potential profile shifts due to changes in conductivities by transformation, (b) conductivity of oxide ions, indicating decrease in the reducing side, and (c) conductivity of electrons, showing that the minimum point, corresponding to the border, is shifting to the reducing side after 1,000,000 s. The dashed lines correspond to the initial and final fronts of NiO reduction given in Fig. 10.

Grahic Jump Location
Fig. 3

Phase diagram for the ZrO2-YO1.5 system based on Yashima et al. [73] phase data for transformation of t′ phase into coherent t and c phase mixtures are plotted as open (tetragonal) and solid (cubic) symbols. From conductivity measurements, stable cubic phase region is obtained and shown as solid circle, whereas region in which the transformation takes place is plotted as open symbols. Composition in the coherent mixture is also plotted as diamond symbols.

Grahic Jump Location
Fig. 5

Experimentally determined area for transformed tetragonal phase detected by Raman spectra. Intensity scale is derived from the peak area ratio between cubic and tetragonal signals in Raman spectra (see Fig. 4(a)) on 8YSZ electrolyte in the flatten tubular cells fabricated as anode-support cells: (a) sample tested for 5000 h at 800 °C in CRIEPI site, (b) sample tested for 5000 h at 775 °C in CRIEPI site, and (c) cells used in demonstration program which was operated for 4070 h under real service environments (operation temperature is thought to be less than 800 °C).

Grahic Jump Location
Fig. 6

Degradation of electrical conductivity of cells consisting of Pt/1 mol % NiO-doped 8YSZ/Pt placed between air and 1.2% H2O/H2 with a parameter of operation temperature. The vertical axis in the right-hand side is the terminal voltage for cells operated under the OCV condition.

Grahic Jump Location
Fig. 14

Summary of phase evolution of 8 at % Y-doped zirconia as a function of Hollomon–Jaffe aging parameter derived from temperature and holding time of annealing test for thermal barrier coating materials. HF parameter is selected at 45,000 and 50,000 as the starting and ending stages of development of mixture of Y-lean tetragonal and Y-rich cubic phases (Reproduced with permission from Lipkin et al. [79]. Copyright 2013 by Wiley).

Grahic Jump Location
Fig. 15

Comparison in cation diffusivity between experimentally determined values (solid lines [8588] and open symbols [89] and model-fitting values based on Hollomon–Josef parameters for phase evolution in thermal barrier coating materials (dashed lines) and the present degradation behavior of conductivity of YSZ with and without NiO doping (dotted lines) given in Table 2

Grahic Jump Location
Fig. 16

Logarithmic time constants for conductivity degradation in YSZ as a function of logarithmic NiO concentration. Solid circle [53] and other symbols [48,50] are for NiO-doped 8YSZ; open triangles are from literature for 8YSZ without NiO doping [42,43] (see Table 1).

Grahic Jump Location
Fig. 17

Schematic drawing for growth of coherent t″ + c mixture in the t′ phase accompanied with high defect concentrated growing front at the interfaces between the t′ phase and the mixtures. NiO in 8YSZ is also accumulated in such growing fronts and increases the cation vacancies on reduction of NiO: (a) pure 8YSZ and (b) 1 mol % NiO-doped 8YSZ.

Grahic Jump Location
Fig. 19

Effective area of the two time-constant model in the oxygen potential versus temperature plot; this represents kinetic effects of transformation of 8YSZ into the t″ + c mixtures. The instability temperature of the cubic phase is given around 1373–1423 K; below that temperature, the cubic phase undergoes the diffusionless transformation to the t′ phase which has the same cation configuration but the different oxygen configuration. Above the nucleation temperature of the t″ + c mixtures, the coherence t″ + c mixtures grow their size with time due to the Y-diffusion from the Y-poor t″ phase to the Y-rich c phase. Between those two temperatures, the transformation-induced conductivity degradation can be represented in terms of the two time constants except for the area where the NiO reduction is delayed due to possible kinetic barriers for nucleation of Ni metals or surface reactions of forming Ni along grain boundaries, both of which are represented by the increasing Gibbs energy drop at the Ni precipitation sites (indicated by the dashed line) with decreasing temperature.



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In